Today is World Book Day in Britain and Ireland, and to parents that means one thing: their child better have left the house this morning dressed as a literary character.

World Book Day, which is celebrated on March 5 in Britain and Ireland, celebrates reading and for the event, children receive book tokens equivalent to one pound that allow them to go to bookstores and get certain titles in exchange for the tokens. They are able to do so for much of the month of March, according to the World Book Day website. Titles that young readers can get with their token include "Elmer's Parade" by David McKee, "Best Mates" by Michael Morpurgo, and "Killing the Dead" by Marcus Sedgwick. Readers can also use their token to purchase a regular book and get a one pound discount. In addition, schools, libraries, and bookstores host various activities for the celebration.

And according to various media outlets, dressing children in book-themed costumes has become one of the most prevalent activities. Telegraph writer Rachel Jones called the activity “the all-important costume.”

Meanwhile, Guardian reporter Sarah Ditum wrote that she felt some pressure to deliver a great costume for her child.

“For the last four World Book Days, my daughter has gone to school dressed as Alice [of ‘Alice in Wonderland’],” Ditum wrote. “This is not because she particularly likes the Alice books. In fact, she hasn’t read the Alice books. It’s because I am a terrible parent and every year I forget about World Book Day… Some mums and dads insist on trying, and apparently some children are reckless enough to encourage them, judging by the joyful tiny faces that you’ll see on Thursday morning peeping out from elaborate outfits. There’s still a minor sheen of snobbery around the store-bought outfit… My resentment on this point, however, really stems from my own incompetence and the fact that I secretly think anyone who is organised enough to get to the shop is probably cheating.”

The US celebrated World Book Night (which takes place in April), which came to America from Europe, for the past few years, but this past summer, the organization behind the event (in which books are handed out for free by volunteers) announced that the event was finished because of lack of funds.